Communication networks, such as computer networks, typically include several interconnected devices that communicate with each other using data units (e.g., packets, frames and so on). Problems may arise in computer networks that may hinder transmission of a data unit from one device to another. For example, in some instances, data units may be delayed before arriving at their destination. Also, some data units may simply be lost entirely and may never arrive at their destination. It may often be necessary to monitor these and other performance parameters of computer networks.